The decision of whether to start a women on the combined oral contraceptive pill is now guided by the UK Medical Eligibility Criteria (UKMEC). This scale categorises the potential cautions and contraindications according to a four point scale, as detailed below:

• UKMEC 1: a condition for which there is no restriction for the use of the contraceptive method
• UKMEC 2: advantages generally outweigh the disadvantages
• UKMEC 3: disadvantages generally outweigh the advantages
• UKMEC 4: represents an unacceptable health risk

Examples of UKMEC 3 conditions include

• more than 35 years old and smoking less than 15 cigarettes/day
• BMI > 35 kg/m^2*
• family history of thromboembolic disease in first degree relatives < 45 years
• controlled hypertension
• immobility e.g. wheel chair use
• carrier of known gene mutations associated with breast cancer (e.g. BRCA1/BRCA2)
• current gallbladder disease

Examples of UKMEC 4 conditions include

• more than 35 years old and smoking more than 15 cigarettes/day
• migraine with aura
• history of thromboembolic disease or thrombogenic mutation